The original tool is shown in FIGS. 1a-1c and 2a-2c. This tool is described in detail in U.S. Pat. No. 8,132,619 that issued in 2012. The detailed operation of the tool is covered at great length in that patent and will not be repeated here. Instead the major components and tool operation of the existing tool will be reviewed below to provide context for understanding the issue with the tool that brought about the improvement to the tool that constitutes the present invention. FIGS. 2a-2c represent the liner hanger packer assembly and FIGS. 1a-1c represent the running tool that fits inside the assembly of FIGS. 1a-1c. 
The liner hanger/packer 10 is shown in FIGS. 2a-2c. It has an expandable slip ring 12 that is separately patented in U.S. Pat. No. 7,607,476 and an adjacent sealing element 14. An upper extension 16 has teeth 18 at an upper end to selectively engage teeth 20 of the running tool 22 for tandem rotation during running in. When assembled for running in, the swage assembly 24 is positioned just above taper 26 above the slip ring 12. The stroker assembly 28 occupies the balance of the upper extension 16 up to teeth 20, during run in. A pup joint 30 has a lower end thread 32 for connection of the liner that is not shown. In operation, the sequence of events is to drill or ream the well with a bit or a reaming shoe at the lower end of the liner and when the desired overlap to an existing tubular is reached, to set the slip ring 12 by expansion resulting from stroking swage assembly 24 a first time. Cementing can then take place with displaced fluids getting past the set slip ring 12 that now bites the existing well tubular that is not shown. After the cementing is completed by the launching of wiper plug 34 as a result of dropping a dart into the wiper plug and pressuring up, the swage assembly 24 is stroked further to expand the sealing element 14 and the running tool 22 is withdrawn.
The major components of the running tool 22 are the stroker assembly 28 that selectively moves the swage assembly 24 after the anchor assembly 36 is engaged. The flapper assembly 38 is engaged to selectively release a flapper 40 to close in preparation for the second stroke of the swage assembly 24 that will then expand the sealing element 14. After the sealing element 14 is set, further pressure buildup breaks a rupture disc 42 in the flapper 40 to avoid pulling a wet string. The stroker assembly is made up of a series of pistons 44, 46 and 48 that are respectively pressured to move downhole through pressure respectively delivered through ports 50, 52 and 54. This can happen when a ball 55 is dropped onto seat 56 and pressure is built up. When that happens, the first event is the setting of the anchor section 36 via ports 58 to stroke a piston 60 that has a lower end connected to slip segments 62. Axial movement of the segments 62 along edge ramps 64 brings the segments 62 radially outwardly into a grip relation to the surrounding pup joint 30 shown in FIG. 2b. Once the slip segments 62 get a bite further pressure increase strokes the pistons 44, 46 and 48 and axially advances the swage assembly 24 to expand the slip ring 12 so that the liner is supported and is ready to be cemented. Further pressure increase after the full stroke of the stroker assembly 28 will then blow ball 55 past the seat 56 as a result of the seat 56 shifting to allow it to open up to let ball 55 pass so that the cement can pass into the liner that is not shown and its associated shoe that is also not shown and into the surrounding annulus in the known manner. Blowing ball 55 past the seat 56 also releases the running tool 22 from the liner hanger/packer 10. The displaced fluid can get past the slip ring 12 because at this time the sealing element 14 is not yet expanded. After the cement is pumped through the wiper plug 34 a dart that is not shown is landed in it to launch wiper plug 34 which concludes the cementing operation so that the sealing element 14 can now be set.
The process of expanding the sealing element 14 first requires that the passage 66 be closed with flapper 40 to enable another stroke of the stroker assembly 28 so that the swage assembly can be advanced again for expansion of the sealing element 14. In order to release the flapper 40 to close, the running tool 22 is lifted to release the support lugs 68 into an expanded portion under the slip ring 12 so that on subsequent setting down weight the flapper 40 can be advanced relative to sleeve 70 so that a spring on the flapper 40 can rotate it 90 degrees to a closed position. The rupture disc 42 in the flapper 40 is still intact at this time so that the passage 66 is closed to pressure applied from above in a similar manner as the original closing of this passage at a higher location to set the slip ring 12 by pressuring up on seated ball 55 on seat 56. This time to set the sealing element 14 the barrier to pressure is further downhole at the closed flapper 40 that is sprung to move down onto a seat to retain applied pressure from above.
It should be noted that for the initial movement to set the slip ring 12 the ball 55 landed on seat 56 isolates access ports 72 from applied tubing pressure. Pressure on ports 58 above the seated ball 55 moves the piston 60 and displaces fluid through then open ports 72. However, with flapper 40 in the closed position to get another stroke of stroker assembly 28 so that the swage assembly 24 can again advance requires that the anchor assembly 36 again become operable. With ball 55 shifting seat 56 to allow it to pass through, it can be seen that the ports 72 need to be blocked off so that pressure against the closed flapper 40 will be directed as before to ports 58 for actuation of the anchor assembly 36. Thus the same setting down weight movement with lugs 68 extended also results in upper end 74 is positioned over the ports 72 from the setting down weight that has moved the ports 72 while the sleeve 70 is supported off landed lugs 68. At this time applied pressure above the flapper 40 that is now closed goes into ports 58 to set the anchor assembly 36 and into ports 50 and 52 to operate the stroker assembly 28 in the manner described for expansion of the slip ring 12 but this second stroke now expands the sealing element 14. When that is done further pressure buildup blows the rupture disc 42 in the closed flapper 40 and the running tool 22 is ready to be removed.
While the description above is a slightly abridged description of the operation of this tool, those skilled in the art can find all the remaining details in the description of the preferred embodiment of U.S. Pat. No. 8,132,619 that is fully incorporated herein by reference as if fully set forth. The above description of the existing tool is intended to provide context to explaining the problem with the existing tool and in so doing the present invention that deals with and solves this problem.
The problem has been the removal movement of the running tool 22 can occur at a fast enough speed such that fluid trying to get through the tool where rupture disc 42 has been ruptured creates a back pressure above the flapper 40 that continues to be in the closed position. This back pressure then communicates with ports 58 that remain open at the same time that the set down movements described above in order to set the sealing element 14 have sleeve 70 blocking ports 72. The generated backpressure acting on ports 58 urges the piston 60 to advance slips 62 along inclined ramps 64 so that a bite is obtained against the casing pup joint 30 that surrounds the slips 62 and the running tool 22 anchors and cannot be removed. In the past when this occurred a release of the slips 62 by forcing them to ride back down ramps 64 was accomplished with another tool feature that allowed rotation of the running tool 22 to mechanically retract the slips 62 with the aid of spring 76 shown in FIG. 1B. The potential problem with this solution is that if there is significant deviation in the wellbore, the effect of rotation at the surface may be negligible at the desired location of the release threads. The solution for all applications and the subject of the present invention is adding an ability to reopen the ports 72 after the sealing element 14 is expanded and by doing so putting the anchoring assembly 36 in pressure balance to passage 66 above the flapper 40 that is in the closed position with the rupture disc 42 in it in the ruptured condition. This pressure balance comes from ports 58 and 72 open at the same time that the running tool 22 is lifted. In this condition, any backpressure raised due to movement of running tool 22 inducing fluid flow through the broken rupture disc 42 will not create a net force on the slips 62 and will also allow the spring 76 to maintain a net force on the piston 60 that in turn will pull the slips 62 back down the inclined edge ramps 64 so that the slips will not bite the pup joint 30 so that the running tool 22 can be removed without mechanical resistance from the anchor assembly 36.
Those skilled in the art will more readily appreciate these and other aspects of the present invention from a review of the detailed description of the invention and the associated drawings while understanding that the full scope of the invention is to be found in the appended claims.